EP 0030294 discloses a process for the preparation of compound of cephalosporin antibiotic as given in scheme 1:
wherein R represents hydrogen atom or a readily hydrolysable ester group and X represents one of the groups
EP patent 0 842 937 discloses a process for the preparation of compound of cephalosporin antibiotic as given in scheme 2:
wherein R is

WO 00/63214 discloses a process for the preparation of cephalosporins by condensation of carboxy ester intermediate with silylated thiourea.
wherein X and R1 are substituents useful in cephalosporin chemistry and RE is hydrogen, a negative charge or together with the COO− group to which RE is attached is an ester, Y is halogen; R′ is hydrogen or silyl and R″ is silyl; R′E is silyl or together with the COO— group to which RE is attached is an ester. The above patent publication discloses an alternate process, which involves the desilylation of compound of formula (II) and then condensation of desilylated compound with thiourea.
WO 02/083634 discloses a process for the preparation of cefpodoxime of formula (I), as shown in scheme 3 below:
wherein R is hydrogen or silyl group and R′ is silyl group or COOR′ is a carboxylic acid salt; X is halogen. The process comprises reacting the compound of formula (IX) with compound of formula (III) and desilylating the compound of formula (X) and cyclizing the desilylated compound with thiourea to produce cefpodoxime acid of formula (XII).
The above processes uses the silylating agent in a solvent for condensation of halo acid of formula (III) with cephem derivative and then desilylating the silylated cephem derivative to react with thiourea to produce desired cephalosporin antibiotic. The present process avoids the use of silylation step and thereby reduces the cost of production and also makes the process simple and easy to implement in commercial scale.
GB 2012276 describes 7-(4-halogeno-3-oxo-2-alkoxyiminobutyrylamino) cephalosporin derivative of the formula (XIII)
wherein X represents a halogen atom, R3 represents —CH2R5 (R5 is hydrogen atom or the residue of a nucleophilic compound),a halogen atom, an alkoxyl group, thiol group, amino group etc., —COOR4 represents a carboxylic group which may be esterified, and R6 represents an alkyl group and also a process for preparing a 7-[2-(2-aminothiazol-4-yl)-2-(syn)-alkoxyiminoacetamido]cephalosporin derivatives of the formula (XIV)
wherein the symbols have the same meanings as defined above, which comprises reacting the above compound (I) with thiourea. This patent also describes a process for the preparation of compounds of formula (XIII), which comprises reacting the compound of formula (III) or its reactive derivative with compound of formula (IX) using organic amine.